Peripheral Dialog for CAN

Transcription

1 C Compilers Real-Time OS Simulators Education Evaluation Boards CAN Simulation with µvision2 Implementation Suggestion for Temic CANray July 26, 2000, Munich, Germany by Hans Schneebauer, Keil Elektronik GmbH This Implementation suggestion describes the CAN simulation with µvision2. With µvision2 it is possible to: Simulate incoming messages and outgoing messages View the CAN communication and the parameters of the CAN controller write signal functions that supply messages automatically. Peripheral Dialog for CAN The µvision2 Debugger offers a CAN dialog that allows you to review the actual settings of the CAN interface. This dialog opens via the main menu under Peripherals CAN. This dialog offers several tabs that are described in the following. CAN Configuration #1: review and modify the general CAN controller registers. (Message ID Mask registers, ect.) CAN Simulation with µvision2 Page 1 of 5

2 Configuration #2: review and modify the CAN Baudrate and Interrupt registers. CAN Channels: review the CAN message object registers including status information CAN Simulation with µvision2 Page 2 of 5

3 CAN Communication: review incoming and outgoing messages. This window works similar to a CAN analyzer and shows all messages on the simulated CAN BUS. CAN Simulation with µvision2 Page 3 of 5

4 Virtual Simulation Registers (VTREG) The µvision2 Debugger implements virtual simulation registers (VTREG) that can be used to review the CAN communication on the Debugger command line level or within Debug and Signal functions. The following registers are implemented: VTREG Description CAN0ID CAN0L CAN0B0 CAN0B7 CAN0IN CAN0OUT CANTIMING Is an 11-bit or 29-bit identifier of the message currently transferred. The ID size is specified with the values in the CAN0IN or CAN0OUT VTREG. For short 11-bit identifiers only the 11 LSB bits are used of this VTREG. The data length of the CAN message. Valid values for CAN0L are 0 8. The data bytes of the CAN message. 8 data bytes are implemented to access the individual message bytes of the current object. Is set by the user or within debug functions to simulate incoming messages. The following values are possible: CAN0IN = 1 receive the current message using a 11-bit identifier. CAN0IN = 2 receive the current message using a 29-bit identifier. CAN0IN = 3 request a remote frame from the application program with matching 11-bit identifier. CAN0IN = 4 request a remote frame from the application program with matching 29-bit identifier. CAN0IN = 0xFF simulate BUSOFF mode of the CAN controller. CAN0IN is set to 0 by the simulator when the message has be processed by the µvision2 simulator. Is set by the simulator when transmitting a message by the application program. The following values are possible: CAN0OUT = 1 transmit the current message using a 11-bit identifier. CAN0OUT = 2 transmit the current message using a 29-bit identifier. CAN0OUT = 3 request a remote frame with matching 11-bit identifier from the user or debug function. CAN0OUT = 4 request a remote frame with matching 29-bit identifier from the user or debug function. Allows you to set a performance factor that controls the simulated communication timing within µvision2. This performance factor simulates a busy CAN network. With a performance factor of 0 an CAN network with infinite baudrate is simulated. With a factor of 1 the CAN messages are transferred in real-time taking care of the current selected communication baudrate. A factor of 2 simulates the performance that is identical to 50% of the communication baudrate. CANTIMING is a floating point value that can be between The VTREG naming conventions CAN0xx is used to allow also the simulation of devices with dual CAN interfaces. On such devices the VTREG names of the 2 nd CAN controller are named CAN1xx Simulate Incoming Messages The following example shows the simulation of an incoming message object with 2 message bytes. >CAN0ID = 0x4500 // message ID = 0x4500 >CAN0L = 2 // message length 2 bytes >CAN0B0 = 0x12 // message data byte 0 >CAN0B1 = 0x34 // message data byte 1 >CAN0IN = 2 // set CAN message with 29-bit identifier to the application program NOTE You may also enter incoming messages directly in the CAN communication dialog page. Process Outgoing Messages By using a breakpoint on the CAN0OUT register it is possible to invoke debug functions. The debug function might check the CAN message object and may send a reply to the CAN message or invoke a signal function that sends a delayed reply. The following example shows the usage: FUNC void CANmessage (void) { switch (CAN0OUT) { case 1: printf ("\nsend Message (11-bit ID=%04X)", CAN0ID); case 2: printf ("\nsend Message (29-bit ID=%08X)", CAN0ID); case 3: printf ("\nrequest Message (11-bit ID=%04X)", CAN0ID); case 4: printf ("\nrequest Message (29-bit ID=%08X)", CAN0ID); break; break; return; return; CAN Simulation with µvision2 Page 4 of 5

5 printf ("\nmessage Length %d, Data: ", CAN0L); printf ("%02X %02X %02X %02X ", CAN0B0, CAN0B1, CAN0B2, CAN0B3); printf ("%02X %02X %02X %02X \n", CAN0B4, CAN0B5, CAN0B6, CAN0B7); >BS WRITE CAN0OUT, 1, "CANmessage ()" // call CANmessage debug function with outgoing messages NOTE All CAN messages can be review also in the CAN communication dialog page. Using Signal Functions With signal functions it is possible to send periodically messages to the user applications. Signal functions are created within the µvision2 debugger. Refer to µvision2 Debug Functions for more information on this topic. The following signal function sends a message with two bytes 10 times per second. The signal function receives an info value that is transmitted to the application program. This info value is constantly incremented: SIGNAL void sendcan (unsigned int info) { while (1) { CAN0ID = 0x4510; // CAN message ID CAN0L = 2; // message length 2 bytes CAN0B0 = (info & 0xFF); // message data byte 0 CAN0B1 = (info >> 8); // message data byte 1 CAN0IN = 2; // send CAN message with 29-bit ID twatch (CLOCK / 10); // send message 10 times per second info++; // increment info value >sendcan (500); // invoke sendcan function Simulating Communication Errors The µvision2 Debugger is not able to simulate directly CAN communication errors. These errors are typically handled within the CAN controller hardware. The user application does not care of communication error conditions since they are automatically handled by the CAN controller. If it is required to simulate error conditions the user might directly set the error status information in the Configuration #2 dialog page. CAN Simulation with µvision2 Page 5 of 5